[daip] rms-display of TVFLG

[Eric Greisen]

Volker Heesen writes:

 > I have a problem with displaying the amplitude/phase inside TVFLG as rms
 > value. AIPS complains like this:
 > 
 > JULIA > TVFLG1: Loading RMS AMPL over window BLC    1     1 TRC  434   180
 > JULIA > TVFLG1: with Stokes RR channel   1 IF #  1 smoothed to   10.00 seconds
 > JULIA > TVFLG1: First compute the smoothed image of desired type
 > JULIA > TVFLG1: TVFOAD: NO VALID RMS'S FOUND - INCREASE AVERAGING TIME
 > 
 > I have already increased dparm(6), the sample time on the
 > y-achsis. This reduces the extend in y-direction of the
 > visibilites. However, it is obviously not the averaging
 > time. Increasing the smoothing and scan time doesn't work either.
 > 
 > Do you have a hint for me, how to fix the problem?
 > 

The RMS is computed from the master grid samples.  If you change
DPARM(6), then you change the master grid but still do not give it
samples from which to compute an rms.

It computes the rms over the "SMOOTH TIME" which should be 3 or more
(i.e. 30 seconds for 10-second data in DPARM(6) and in the
observation).  The rms computation is broken whenever the averaging
would break such as over source boundaries.  Also if you tell it
DPARM(6) = 10 and the observations are on a 30-second interval, then
there will be only one sample in the default smooth time and no rms is
possible.

I just ran the task to make sure of all this and it ran fine even with
a smooth time of 2 but gave the above messages exactly with a smooth
time of 1 (and data sampling on 10sec intervals)

Eric Greisen